1. Field of this Invention
This invention relates to a new method of taking cell smears for diagnostic examination in which a specimen of the skin, a mucous membrane or other body area to be examined is collected by means of a swab and diagnostically examined. This invention also relates to a new type of swab specially developed for use in such method.
2. Prior Art
Cell smears are taken from the skin, a mucous membrane or other body area by means of a swab and then applied to a glass slide. This type of sampling is of great importance in gynecological cytology or for smear examinations in other medical disciplines, e.g., in dermatology, in surgery (collecting cellular material from the bronchus or the esophagus) and in gastroenterology (collecting cells from the stomach and other regions of the intestinal tract).
The methods of sampling in general have been repeatedly modified in the last few years with a view to improving the diagnostic value which depends to a large extent on the sampling technique. Among the instruments used in gynecology for taking cell smears are hard implements, such as tongue blades, concave wooden spatulas and Ayre's spatulas of similar shape [Wied, (1974) Soost, (1974); and Wheeless and Oderdonk, (1974)]. But at the present time preference is given to cotton swabs, which have the advantage of causing less mucosal lesion during sampling. Moreover, a cotton swab can be prepared in the dimension most favorable for the site of sampling.
In gynecology smears are usually taken by collecting cells from the vaginal cavity, from the portio surface and from the cervical canal and applying them to a glass slide, which is then examined microscopically after Papanicolaou staining.
In cancer diagnostics, for example, early recognition of the disease is dependent not only on careful cell sampling adjusted to the site of cancer generation but particularly on obtaining a representative specimen of the cellular material suitable for evaluation, because frequently even very few cells of small size may determine the result of the diagnosis.
The most important demands made by cytopathologists upon the specimen to be examined may therefore be summarized as follows:
A. a qualitatively adequate supply of cells on the slide; and PA1 B. a cell pattern without mechanical cell lesions (artifacts of preparation).
If the specimens sent to the laboratory by gynecologists and, in particular, by general practitioners are evaluated with respect to these criteria, it is found that for a certain percentage of these specimens a cytological diagnosis is not possible, or only with reservations, mainly because too little cellular material is contained in the smears. As a consequence, many patients have to be given reappointments for taking a second smear. Gynecologists experienced in prescreening report that these patients often do not come again or, experiencing the "fear of cancer", are exposed to intense psychic stress.
The cellular material taken with a cotton swab and applied to a glass slide does not always meet the diagnostic requirements even if the necessary conditions are fully satisfied. The smear spread on the slide is only a part of the total specimen collected with the swab and, therefore, is not necessarily representative of possible pathological changes at the site of sampling. It was found that many cells keep adhering to the surface of the swab and especially between the cotton fibers. A good smear on a slide normally contains 15,000 to 25,000 cells; however 50 percent or more of the total specimen is left in the cotton swab and is lost for the diagnostic evaluation unless recovered by additional complicated washing processes and then converted into a suspension.